TCC Solenoid
 

My car cant decide whether or not to be in lockout right around highway speeds or cruising speeds (above 45) the tranny will bounce back and forth in and out of lockout code reads P1860 TCC Solenoid. My question is does this sound like if I replace the TCC solenoid will that fix it. Car shifts fine runs smooth no harsh shifts ever fluid level is good and pink no metal or chunks in it but it is really anoying when it bounces and trys to engage the clutch. It also kills the MPG because the RPMs are higher than they would be normally. i have seen the video and how to replace it just wish there was a better way to get to it then damn near pulling the engine. Any advice on this will be helpfull

What car are we discussing here? From the sound of it, it appears to be something with a Northstar/4T80E trans. If so, changing the TCC solenoid will most likely NOT solve the problem, tho the solenoid may indeed be melted, or otherwise defective. The main problem with this code is the seals in the channel plate that seal the converter lock-up feed oil...the seals wear, and the lock-up oil pressure drops to almost nothing, which causes the LU to engage/slip/disengage, and then set the code. When the seals leak, the TCC solenoid is commanded by the PCM to try to stop/control the slip, which causes the solenoid to overheat, and usually melt.
The only way to correct this issue is to remove the trans, and replace the two seals and TCC solenoid. The torque converter should also be replaced, since it has been subjected to repeated slippage.
It's not an easy job, by any means....

Hey thanks for the heads up on that now the only question is is it cheaper to light the car on fire and go buy a different one or to have a shop charge me out the A$$ to fix this one. Why is it that cadillacs do this and yet my Yukon XL Denali and my Suburban both the same year as my DTS (2002) that have over double the mileage (200K each) have never given me any problems at all?

Not the same transmissions...or designs. In this particular case, it is the design of the seals themselves. They were redesigned once to make them a little more durable, but the actual compound of the seal is just too hard. So far, the aftermarket has not made anything better, since the 4T80E is only used in a limited number of vehicles(Cadillac only now).
We usually get around $3000 for an overhaul on these things....very labor intensive to remove/replace.

That sounds about right I called a very reputable shop around the Spokane area and I was quoted 1750 to do the seals, TCC seloniod, and Torque Converter if needed. Do you think it is worth it to just put a new trans in with a warranty? They also said it might not be a bad Idea to do head gaskets while they have it apart. What do you think? And thank you very much for taking the time to answer mine as well as many others questions.

Whether or not it's worth it depends on how much you like the car, really. I recently had to do the 4T80 in one of my own cars. I just swapped it out for one I already had built to save down time. If the car was a big turd, and I was having a lot of other problems with it(other than the trans), I might not have done it. I've sent several of my Cads to the junk yard(or a "Cars for Kids" program) because they weren't worth me putting any more $$$$ or time into them.
Honestly, I wouldn't go thru the trouble of removing/replacing the trans, and tearing into it to replace the TCC seals without overhauling it. That's just me...I'm in the trans business, so I can do my own stuff fairly cheap.
Overall, the trans is a pretty good design...really heavy duty, but there are some wear issues with the clutches, and the overdrive band. If the OD band burns, it can take the reverse input drum with it...not exactly a cheap deal.
Couldn't say about the head gaskets....I see a LOT of issues with them on this site, so there's obviously a problem with them, but you'll see that with any all aluminuminum engine, imo. Again, it just depends on how well you like the car, and how long you want to keep it.
hth :D

Anyone familiar with the electrical in 1999 sls caddy. I put a brand new bat. in car year 1/2 ago runs fine. Winter comes, gets too cold over night battery is drained must jump in morning, and it starts right up. Has 57,000 original miles 1999 sls. Take real good care. Does anyone have a troubleshooting thought on where I should start w/o it costing me a face job? Any suggestions would highly valuble.
Respectfully,
D.A. Clark

@Adams Apple
Thank you for assisting with the trans trouble I wrote about a couple weeks ago.
1998 Seville STS
To summarize, P0741 code (and a few other trans related codes) appeared (about after the time I changed out the high pressure PS hose) and the trans was in single shift - emergency mode.
Took it to a dealer (Stevinson Chev - Lakewood, CO) for confirmation of the bad news - an overhaul was assumed.
The fluid was clear and no shavings were found.
I had not taken up the slack in the PS hose sensor wiring, and it's rubbing on the drive shaft caused a bare wire.
The transmission and the PS hose electrical are on the same circuit. A blown fuse caused the transmission to go into it's fail safe mode.
A hundred dollars for: the inspection, dropping the pan and changing fluid and filter, and a 10 A fuse

How is the vehicle running today? I hope that trip get things resolved.

Michelle, Cadillac Customer Service

I have a question about that also, I have a 1994 SLS that gets code P039 past about 45 and it turns off under.

I know I need to flush the trans and install a new filter but did the 94 have a TCC? If so is it under the trans oil pan like other models or inside the trans?

Does the TC on a 94 have a plug to drain it or will I need to have it flushed by someone?

Glad you got it taken care of without a rebuild! You didn't mention any other codes in your original post. Power for the shift, and lock-up solenoids are on a separate circuit from the EPC solenoid, but a bare wire(or 8!) can definitely ruin your day!

Again...P039 is still a Torque converter slip code. Still a problem with the 4T80E trans. I don't recommend flushing a trans, ever, but that's just me. The TCC solenoid is inside the side cover...not accessible very easily at all.

CIRCUIT DESCRIPTION
The Torque Converter Clutch (TCC) solenoid controls the hydraulic fluid for apply or release. The diagnostic test checks for a torque converter clutch not engaged or slipping condition by monitoring the slip speed. Slip speed is the difference between engine speed and transaxle turbine speed. When the TCC is applied, the engine is coupled directly to the transaxle through the TCC. Almost no slippage should occur, so the slip speed is nearly 0. If rpm is too high at a given speed, the Powertrain Control Module (PCM) diagnosis the condition as the TCC slipping or not engaged and Code P039 is set.

TEST CONDITIONS

1. Codes P024, P026, P027, P028, P031, P032, P034, P056 and P075 not set.
2. Transaxle in 3rd or 4th gear.
3. Engine running.
4. TCC commanded "ON" (100%).
5. Transaxle not in park or neutral.
6. Throttle position switch open.
7. Delivered torque from engine not 32 ft lb or less (coast down condition).
8. Delivered torque from engine not 508 ft lb or more (engine under extreme load (Example: towing a trailer or wide open throttle).

FAILURE CONDITIONS
3.71 Final Drive (VIN 9) - Slip speed 48 rpm or greater for 4.5 seconds.
3.11 Final Drive (VIN Y) - Slip speed greater than acceptable value based on engine torque delivered for 4.5 seconds. Refer to chart in accompanying image for acceptable TCC slip values.

ACTION TAKEN

1. PCM turns "ON" the Malfunction Indicator Lamp (MIL) (Service Engine Soon).
2. TCC is disabled for the entire ignition cycle.

NOTES ON FAULT TREE
(Part 1 of 2)

1. Testing Torque Management Brake Switch input to the PCM PI71. If test passes, the display will change from HI 0 to HI X. If test fails, the display will not change.
2. Checking for an open in CKT 420 between C129 and C101.

(Part 2 of 2)

1. Checking for open or shorts inside the transaxle. The resistance should be between 10 and 40 ohms.
2. Checking if CKT 422 is open or if the PCM is unable to control the output.
3. Checking PCM's ability to control the TCC output.
4. Checking if TCC is operating correctly by checking amount of TCC slip when clutch is engaged.

NOTES ON INTERMITTENTS
Intermittent code P039 setting may be caused by delayed TCC engagement (usually the first apply after a cold start) or by TCC slippage during high engine load conditions. Delayed TCC engagement can be checked using PCM 0utput Override PS01 (TCC Solenoid) to disengage and engage TCC and time how long it takes TCC to engage by watching PCM Data PD73 (Torque Converter Slip Speed). Delays of over 5 seconds may cause the code to set. TCC slippage during high load conditions can be determined by looking at code P039 Snapshot Data. High throttle angle (PD01), MAP (PD02), and engine coolant temperatures (PD04) may indica!e a high load condition. Duplicating the high load conditions may cause the code setting conditions to occur.

What kind of prices can I expect as far as parts?

Thanks for this info! I am having the same trouble with my 01 STS. The mechanic I have been using has been telling me that I need to replace the camshaft sensor (this is after i paid him to replace the crankshaft sensors and oil pressure switch and he said the camshaft sensor was fine). He just lost a customer! So glad I found this

Po174
 

Hello I'm new here, I have a 1996 Cadillac Deville with the Northstar V-8 engine.My wife purchased the vehicle from her uncle for 3 grand against my advice.We had the car less than a month and the transmission out of the blue went from driving good to driving 60mph @ 4600rpm's.I plugged it in and had a code of PO174.I'm needing to know my options before I jump into this job.I called a tranny shop and told them the code and they said it would be about 2800.00 to fix it but didn't give any details of what is wrong.I've done some research and I'm not sure on what to-do.It has the 4T80E Tranny.There is no slip or oder, the fluid is clean and no shavings.Any advice would be appriciated.I'm a mechanic but not a transmission expert.Thanks Guys....

Po174
 

Hello I'm new here, I have a 1996 Cadillac Deville with the Northstar V-8 engine.My wife purchased the vehicle from her uncle for 3 grand against my advice.We had the car less than a month and the transmission out of the blue went from driving good to driving 60mph @ 4600rpm's.I plugged it in and had a code of PO174.I'm needing to know my options before I jump into this job.I called a tranny shop and told them the code and they said it would be about 2800.00 to fix it but didn't give any details of what is wrong.I've done some research and I'm not sure on what to-do.It has the 4T80E Tranny.There is no slip or oder, the fluid is clean and no shavings.Any advice would be appriciated.I'm a mechanic but not a transmission expert.Thanks Guys....

PO174 is NOT a transmission related code. It is Fuel trim System Lean on Bank 2. How a trans shop could tell you you need a trans just by that code is interesting.
You may have a vacuum leak somewhere that is causing a skewed MAF, MAP, or other sensor reading that could set that code, and also keep the PCM from commanding the trans into Lock-up, which would cause your higher RPMs.
You might certainly have a trans problem, too, but the code you posted is not enough info to attempt to diagnose a trans problm.
However....if you remember the code incorrectly(or like me, are slightly dyslexic), and what you have is actually a P0741, then we have a different story....are you certain you have a P0174?

I drive a 2003 Seville with the 4t80e tranny. The tcc solenoid failed, and I am in the process of replacing by accessing the side panel. Supposedly a clip holds the solenoid in place, but upon inspection, I do not see a clip. The shop manual diagram shows a u shaped clip with a loop that could be hooked. Are there other clips used that do not have the loop?

The clip is there...it may be twisted down into the channel where it is hard to see, but it is there. You can get a small screwdriver, or pick in the top part, and pull it straight out. I have posted pics of these things several times here....still looking for them....
If the plastic on the solenoid is melted, or looks burnt in any way, replacing the solenoid might solve the problem for a little while...until the solenoid melts again. The problem that normally causes the solenoid to fail or set a code is actually leakage in the hydraulic circuit for the lock-up. The PCM sees the converter slip, and ramps the solenoid up to try to control the slip, eventually getting to a point to where the solenoid is "ON" all the time, instead of being pulsed on/off(PWM). The solenoid is not designed for that kind of situation, and it eventually gets too hot, and melts.

tcc solenoid replacement
 

OK, I just completed the TCC repair on my 2003 SLS with the 4T80E. SES light was on with codes 741 and 1860. It took much longer than expected do to this being my first attempt. A couple critical details could have reduced the process considerably. I took 102 photos and a full page of notes to create my own how-to manual. Before you attempt this just know that the GM engineers designed the transaxle not to be serviced without removal from the vehicle. The upper valve control side cover is positioned pretty much against the frame. Several bolts require stubby wrenches, and the retaining clip is very challenging. And it does get messy, so have plenty of cardboard, drip pans and floor dry handy to capture and control the fluid spills. I purchased my solenoid on Amazon for $30. Transmission shops quoted $1700, but included additional components, like a new torque convertor. The Seville is back together and running without the SES light, so I am calling my effort a success.......for now at least.

I just visited my local and reliable transmission repair shop in Rosemount Mn. He was kind enough to perform a diagnostic test drive at no charge using his Snap-On analyzer. I had previously replaced only the TCC solenoid. No codes activated during the test. His analyzer did show some slippage due to the viscous torque converter of between 50 and 140 RPM, again , not enough to trigger my computer to issue a code. The 140 range was only achieved going up hill at 65 MPH during acceleration. Find a good transmission shop and ask them to perform a similar test drive.

I hope that fixes it, but the specs for converter slip is -20 rpm to 100 rpm slip. When the TCC is applied, the engine is coupled directly to the transmission through the TCC. The TCC slip speed should be near 0. If the PCM sees a slip of greater than the maximum allowed(100 rpm in this case) for more than 4 seconds under a given engine torque, it will set the code.
Fingers crossed!!

tcc solenoid
 

Ok, seven months and several thousand miles after replacing just the tcc solenoid after it had melted and mal-functioned, the transmission is working fine, no service lights or codes.

In another thread, a transmission mechanic said the TCC Solenoid fails due to internal issues. But, when my Cadillac dealer looked at it, they said ONLY the TCC was bad. Similar to others, they wanted $1800 to replace the $30 part. My Extended Service contract would not fix either internal seals or the solenoid, so I can do nothing but "live with it". So, this is proof that the TCC Solenoid WILL go bad on its own.

TS

2002 Cadillac Deville, with 128000 miles looks garage kept only paid 600.00
 

what all do u mean overhaul or rebuildt ,I'm getting a trouble code, p0741 tcc stuck off??I know it needs a torque converter probably an Solenoid plus the seals where the shaft is ,is there any thing else that yall do,I know an filter an gaskets.i mean it shifts fine an all ,the only thing I can feel the torque converter tho ,but seems to be fine tho ,so is there anything else or what ??thanks for ur time in advance, when u get a chance thanks 😊

"Overhaul" or "rebuild"--along with "remanufacture"--all signify about the same thing. There's no legal distinction among those terms, although if you believe the propaganda, "remanufacturing" is somehow, mysteriously more involved and more complete and therefore "better" than the other two.

Point is, the entire transmission is taken apart, all parts inspected, and replaced if faulty. There are usually various upgrades done at the same time--high-failure parts replaced with stronger items, for example. The transmission should come out of the process "better than new"; but of course that's going to depend on the level of attention given to each one of the hundreds of pieces inside an automatic transmission. Which is why the last two (rear-wheel-drive, 4-speed overdrive) transmissions I had overhauled by my favorite local shop were about $3000 each; and they weren't as complex to begin with as your Cadillac transaxle. An overhaul/rebuild/remanufacture of a transmission is not for sissies; and it won't be inexpensive unless you're Bill Gates.

If that were mine, I'd take it to a reputable transmission specialty shop, and ask them for their opinion--and estimates of both time and money for repairs. MAYBE you don't need a complete overhaul. Perhaps a replacement solenoid, harness, fluid flush plus filter, would fix the problem. Who knows? Maybe it's as simple as a broken wire in the wire harness, or a bad connection.

No telling until it's been examined. In MY driveway, the first thing that would happen is to connect a scan tool, drive the car, and see if the computer is commanding torque converter lockup--and see if the engine RPM drops when it does so. If that happens, I'd clear the code and see if it comes back. If the code doesn't come back...problem solved.